Article conveying roller conveyors having drives using flat or V-shaped belts, or having round belts or ropes for driving the rollers are well known. Conveyors of this arrangement are exemplified by Taylor U.S. Pat. No. 2,129,510 of Sept. 6, 1938, or Pevear U.S. Pat. No. 2,002,830 of May 28, 1935, or Eggleston U.S. Pat. No. 1,959,157 of May 15, 1934. More recently the roller conveyor of Gotham U.S. Pat. No. 3,323,636 of June 6, 1967 has disclosed a round belt drive in connection with straight line conveyors, while Fleischauer et al. U.S. Pat. No. 3,610,406 of Oct. 5, 1971 has utilized a V-shaped belt for a straight roller conveyor. These examples tend to show that V-shaped belts are generally better adapted to straight sections, while round belts or rope are capable of driving rollers supported in curved sections, as well as straight sections.
The problem with rope drives for conveyors has been that the rope is sensitive to changes in humidity and can become excessively tight or loose so that uniform drive conditions are difficult to maintain. The advantage of rope drives is that the length of the drive can be quite long, being of the order of several hundred feet. The V-shaped belt, on the other hand, has largely replaced the rope drive on the basis of its better contact and less sensitivity to humidity conditions. However, the splice in V-shaped belts has reduced the length that can be used, thereby requiring short lengths of conveyor sections and drive transition means to couple the short conveyor lengths to make up the full length desired. The short length limitation for V-shaped drive belts is dictated by the strength of the splice, and the tension the belt can stand.
In addition to the limitations inherent in rope and V-shaped belt drive means, there is the added problem connected with conveying articles packaged in shrink wrap film. This type of film has an inherent characteristic of being tacky which means that the film tends to stick to almost any material. Coupled with the shrink wrap film problem, there is the noise problem of the splices in the rope or V-shaped belt drive means hitting the rollers, and this noise is especially undesirable if the splices are large.